An example of a conventional member for mounting semiconductor light-emitting elements is described in Japanese Laid-Open Patent Publication Number 2002-232017.
In the semiconductor mounting member described in this publication, a substrate and a ceramic window frame surrounding a light-emitting element is formed from a ceramic having as its main component aluminum oxide, aluminum nitride, or the like.
With the increase in output in light-emitting elements in recent years, there has also been an increase in heat generated by semiconductor light-emitting elements. When a ceramic having aluminum oxide as its main component (hereinafter referred to also as alumina) is used in the substrate and the window frame, adequate heat dissipation is not possible, leading to increased temperature.
Furthermore, if aluminum nitride, which has high thermal conductivity, is used, the raw material is more expensive and harder to process than alumina. Furthermore, if a metallized layer is formed on the surface, a metallized layer having W or Mo must generally be formed first. In such cases, a method is used in which a metal paste having W or Mo as its main component is first applied to a green sheet and then this is fired together with the main aluminum nitride ceramic unit (co-fired metallizing). With this method, however, thermal deformation and the like take place during firing, making it difficult to precisely form a metallized layer with a fine pattern, e.g., of less than 100 microns.